| Ribosome recycling factor | |||||||||
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| Identifiers | |||||||||
| Symbol | RRF | ||||||||
| Pfam | PF01765 | ||||||||
| InterPro | IPR002661 | ||||||||
| CATH | 1ek8 | ||||||||
| SCOP2 | 1ek8 / SCOPe / SUPFAM | ||||||||
| CDD | cd00520 | ||||||||
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| MRRF | |||||||||||||||||||||||||||||||||||||||||||||||||||
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| Identifiers | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Aliases | MRRF, MRFF, MTRRF, RRF, mitochondrial ribosome recycling factor | ||||||||||||||||||||||||||||||||||||||||||||||||||
| External IDs | OMIM: 604602; MGI: 1915121; HomoloGene: 12203; GeneCards: MRRF; OMA:MRRF - orthologs | ||||||||||||||||||||||||||||||||||||||||||||||||||
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| Wikidata | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Ribosome recycling factororribosome release factor (RRF) is a protein found in bacterial cells as well as eukaryotic organelles, specifically mitochondria and chloroplasts. It functions to recycle ribosomes after completion of protein synthesis (bacterial translation). In humans, the mitochrondrial version is coded by the MRRF gene.
The ribosome recycling factor was discovered in the early 1970s by the work of Akira Kaji and Akikazu Hiroshima at the University of Pennsylvania.[5][6][7][8] Their work described the requirement for two protein factors to release ribosomes from mRNA. These two factors were identified as RRF, an unknown protein until then, and Elongation Factor G (EF-G), a protein already identified and known to function in protein synthesis. RRF was originally called Ribosome Releasing Factor but is now called Ribosome Recycling Factor.
RRF accomplishes the recycling of ribosomes by splitting ribosomes into subunits, thereby releasing the bound mRNA. This also requires the participation of EF-G (GFM2 in humans).[9] Depending on the tRNA, IF1–IF3 may also perform recycling.[10]
The crystal structure of RRF was first determined by X-ray diffraction in 1999.[13] The most striking revelation was that RRF is a near-perfect structural mimicoftRNA, in both size and dimensions. One view of RRF can be seen here.
Despite the tRNA-mimicry, RRF binds to ribosomes quite differently from the way tRNA does.[14] It has been suggested that ribosomes bind proteins (orprotein domain) of similar shape and size to tRNA, and this, rather than function, explains the observed structural mimicry.
